The changes California's governor said were a condition of his signature on a controversial vaccine bill have cleared their first hurdle with passage in the Assembly of a companion bill. That bill was then sent to the Senate for a vote that was expected to take place on Monday afternoon.

Governor Gavin Newsom last week asked for more changes to the latest vaccine legislation sponsored by Senator Dr. Richard Pan which aims to crack down on doctors who sell fraudulent medical exemptions to those who don't want their children to be vaccinated.

Lawmakers sent Newsom that bill last week, but Pan agreed to carry follow-up legislation giving school children grace periods for existing medical issues that vaccination risky. The grace periods could last several years.

The companion bill also makes it clear that enforcement won't start until 2020. It also eliminates a requirement that doctors swear under penalty of perjury that they're not charging fees to fill out medical exemption forms.

Opponents of the legislation gathered at the Capitol in Sacramento on Monday and blocked one entrance to the building. Several people were detained during that very vocal demonstration.